The present invention relates generally to structural assemblies for joining together the ends of duct parts and more particularly to a flanged joint assembly suitable for fastening at their ends a pair of ducts made of sheet material and having a substantially rectangular cross sectional configuration. The invention is particularly suitable for use in connection with aerodynamic high-pressure plants where a particularly secure and fluid-tight joint is required.
In the connection of duct parts of aerodynamic high-pressure plants, it has previously been known to install predrilled flanged angle section frames made of angle iron over the ends of the duct parts which are then riveted or spot welded upon the duct parts. The flanged angle section frames are raised a distance above the duct parts to an extent that the ends of the duct parts project 3 to 4 mm over the end faces of the flanged angle section frames. The projecting metal strips of the duct parts are then flanged by 90.degree. until the metal strips bear tightly on the vertical end faces of the angle sections. The duct parts provided in this way with the flanged angle section frames may then be joined with each other by screws.
Such a joint is relatively tight, particularly when a packing is inserted between the flanged frames before the duct parts are bolted together. However, a known joint of this type is rather elaborate. The individual parts of the flanged angle frames must be cut to miter and be bolted with each other. Subsequently, a weld existing at the end faces of the flanged angle frames must be surface ground and bores which are either drilled or punched must be provided in the flanged frames for fastening the individual duct parts. After the flanged frames have been applied on the individual duct parts, they must finally be provided with a suitable surface finish, for example, a coated zinc dust paint. Only then may the individual duct parts be bolted with each other.
A flanged joint of the aforementioned type is disclosed in U.S. Pat. No. 31,712,650 wherein the arm of the vertical flange facing the flange extending parallel to the duct side wall extends only to about mid height. The arm passes over an angle of less than 45.degree. into an inclined region which is formed by a horizontal section. Because of the inclined course of the arm part, this known flanged joint is found costlier to manufacture so that the sections are relatively expensive. In addition, the mounting angle plates to be inserted into the flanges must be exactly adapted to the flanges otherwise the joint which is formed will not be stable. Finally, these mounting angle plates must be deburred in the range of the arms which are introduced into the flanges, otherwise there would occur jamming when they are inserted into the flanged sections primarily due to the fact that the cold-rolled sections have unavoidable inside radii at their deflection points where sharp edged arms of the mounting angle plates will chafe thereby impeding an easy introduction.
The present invention offers a joint assembly which features the advantage of being low in cost and stable in its construction. The tightness of the joint is improved by the arrangement of the present invention and a relatively air tight duct joint may be achieved. Furthermore, in joints of this type some criticality exists with regard to the tightness of the corner regions of the joint and packing difficulties which may be caused by dimensional tolerances may appear in regions of the flanged joint. Thus, the invention is directed toward providing an assembly which enables general improvement in the packing of the joint.